What is Soil? :

History of Our Food :

History of Our Food Hunter-Gathers
Small groups of people follow prey animals for food
Small groups of less than 200, with no specialized roles M.Bregar (Dante C.S.S.) 3

Slide 4:

M.Bregar (Dante C.S.S.) 4 The Persistence Hunt(for class viewing)

Slide 5:

M.Bregar (Dante C.S.S.) 5 The Persistence Hunt(for online viewing)

History of Our Food :

History of Our Food Agricultural Revolution
When human beings began to “domesticate plants”
Took place about 10,000 years ago
Most relevant in the fertile crescent (7000-9000 B.C.) M.Bregar (Dante C.S.S.) 6

Agricultural Revolution :

Agricultural Revolution M.Bregar (Dante C.S.S.) 7

Fertile Crescent :

Fertile Crescent M.Bregar (Dante C.S.S.) 8

Importance of Agriculture :

Importance of Agriculture Agriculture resulted in a food surplus
Food surplus allow for population growth and more free time
Developments like job specialization, language, culture, etc. M.Bregar (Dante C.S.S.) 9

Why is Soil Important? :

Why is Soil Important? Soil provides plants with nutrients
The proper management of soil is important to maintain a food supply (food crops)
Why should we be worried?
World’s population is growing,
There is increase demand for food but a limited supply of soil 10 M.Bregar (Dante C.S.S.)

Slide 15:

Easter Island Explained(for online viewing) :

What Happened? :

What Happened? :

What Happened? M.Bregar (Dante C.S.S.) 18

Slide 19:

M.Bregar (Dante C.S.S.) 19

Slide 20:

M.Bregar (Dante C.S.S.) 20

Slide 21:

M.Bregar (Dante C.S.S.) 21

Why is Soil Important? :

Why is Soil Important? Soil is a non-renewable resource
How is soil being lost?
Erosion – soil is washed away into water (streams, rivers, etc)
Urbanization – cities are typically built in the best “growing areas” for plant crops 22 M.Bregar (Dante C.S.S.)

SOIL LAYERS :

SOIL LAYERS 23 M.Bregar (Dante C.S.S.)

Soil Layers :

Soil Layers Soil is formed of different layers called HORIZONS
Each layer of soil has different chemical & physical properties
As you go dig deeper, the soil:
Becomes coarse (rockier)
Amount of organic (living) matter is reduced 24 M.Bregar (Dante C.S.S.)

Soil Layers :

Soil Layers 25 M.Bregar (Dante C.S.S.)

Litter Layer – “O Layer” :

Litter Layer – “O Layer” Uppermost layer, about 1 inch thick
Made of dead organic (living) material which is decomposing
These nutrients will enter into the soil
The litter layer acts like a blanket and limits water loss and temperature change 26 M.Bregar (Dante C.S.S.)

Topsoil Layer – “A Layer” :

Topsoil Layer – “A Layer” Uppermost layer, most important to life
Layer with most organic material and most microorganisms
Layer in which plants grow, rich in nutrients, oxygen, and water 27 M.Bregar (Dante C.S.S.)

Ground Water :

The Water Table :

Water Table :

Water Table Rain water and surface water become ground water in a process called percolation
This ground water accumulates in a location above bedrock called the WATER TABLE M.Bregar (Dante C.S.S.) 33

Water Table :

Water Table M.Bregar (Dante C.S.S.) 34

Aquifer :

Aquifer Aquifer are areas saturated with usable ground water
These are actual pockets of ground water, which will feed local rivers, streams, and lakes M.Bregar (Dante C.S.S.) 35

Slide 36:

M.Bregar (Dante C.S.S.) 36

Aquifer :

Aquifer M.Bregar (Dante C.S.S.) 37 When using a well, we are extracting ground water from an aquifer

Soil Formation :

Soil Formation 38 M.Bregar (Dante C.S.S.)

Step 1: Weathering :

Step 1: Weathering All soil begins as bedrock, so soil begins from the bottom up
Wind, rain, frost, and snow breakdown bedrock into smaller and smaller particles – this is WEATHERING 39 M.Bregar (Dante C.S.S.)

A closer look at Weathering :

A closer look at Weathering 40 M.Bregar (Dante C.S.S.)

Step 2: Enriching the Soil :

Step 2: Enriching the Soil After thousands of years, you have a thin layer of soil which allows small plants to grow
When the plants die, their decaying remains add organic material which enriches the soil 41 M.Bregar (Dante C.S.S.)

Enriching the Soil :

Enriching the Soil 42 M.Bregar (Dante C.S.S.)

Step 2: Enriching the Soil :

Step 2: Enriching the Soil More and more plants died (thousands of years), eventually layers of soil get deeper & larger and larger plants can place roots and live there 43 M.Bregar (Dante C.S.S.)